Field of the Invention
The present invention relates to a device for testing the application state of a plurality of strips of fiber reinforced plastic tape affixed in rows on the surface of a structure.
Background Information
Fiber reinforced plastic sheets have been used in recent years in sports applications and in aerospace applications that require a lightweight and high-performance structure. Many sheet-like molding intermediate materials in a semi-cured state in which carbon fiber has been impregnated with a thermoplastic resin, which is called prepreg, have been used in aerospace applications in particular. This prepreg is formed by making a multilayer laminate on a structure and then curing with heat.
When a curved surface such as a cylinder, typified by an aircraft fuselage, is formed, if a prepreg in the form of a wide sheet is applied so as to conform to the surface shape of a curved structure, the prepreg tends to wrinkle. Accordingly, when prepregs are affixed and laminated on a curved surface, the sheet is appropriately sated and applied in the form of narrow strips of tape, which are evenly laminated and built up.
Also, the strength of a prepreg is different in the direction in which the fibers extend and in the direction intersecting these fibers. Therefore, when a prepreg is applied and laminated over the fuselage portion of an aircraft, the orientation of a layer is always changed by at least 45 degrees from that of the underlying layer so that the direction in which the fibers extend will be vertical, diagonal, horizontal, diagonal, and so on, and this lamination involves from about 50 to 100 layers. Also, anywhere from a few strips to about 50 strips of prepreg are generally applied all at once for a single layer.
The prepregs applied in the form of narrow strips of tape as discussed above are tested for their application state, such as whether they are arranged at a specific spacing from each other, or overlapping each other, etc.
This test is sometimes performed automatically while the prepregs are being applied (see Japanese Patent No. 4,691,562 (Patent Literature 1) and Japanese Translation of PCT International Application Publication No. 2009-531715 (Patent Literature 2), for example), but uneven positioning of the front and rear ends where the prepreg is applied, or the adhesion of foreign matter that may occur due to problems along the supply path could not be tested for. Accordingly, it was essential for a human to visually inspect the result after each layer was finished being applied.